The present invention generally relates to liquid heating apparatus and, in representatively illustrated embodiments thereof, more particularly provides variously configured fuel-fired high efficiency water heaters.
Fuel-fired water heaters of conventional construction typically have a glass-lined metal tank adapted to store a quantity of pressurized water received from a source such as a city water supply. A combustion chamber having a fuel burner associated therewith is positioned in a heat exchange relationship with the tank, usually at the upper or lower end thereof, and communicates with a central flue extending vertically through the tank water. During firing of the burner, hot combustion products created by the burner flow vertically through the flue to conductively transfer combustion heat to the stored water as required. Combustion products exiting the central flue are discharged to a suitable vent system external to the water heater.
While this relatively simple conventional water heater construction has for many years been well suited for its intended water heating purpose, fuel-fired water heaters of this general type are being subjected to increasingly stringent government efficiency requirements. These requirements have triggered a need in the water heater industry for a fuel-fired water heater design which meets the new efficiency requirements, preferably utilizing components and manufacturing techniques similar to those used in conventional water heater constructions, and utilizing improved heat exchanger materials similar to those used in fabricating the tank portion of the water heater, without unduly increasing the overall manufacturing cost of the more efficient water heater. It is to this need that the present invention is primarily directed.